More unit tests. Fixes: 27236, 27126, 27229, 27230, 27231, 27232, 27235 [TFS Changeset #66358]
[TFS Changeset #66309]
Fixes many data layer issues: 27044, 27045, 24237, 27042, 27043, 27046, 27070, 27072, 27073, 27074 [TFS Changeset #66135]